Knee Osteoarthritis (OA), Postoperative Pain
Conditions
Keywords
Biceps Femoris Short Head Block, Adductor Canal Block, Total Knee Arthroplasty, Regional Anesthesia, Knee Osteoarthritis, Enhanced Recovery After Surgery (ERAS)
Brief summary
Total knee arthroplasty (TKA) is frequently associated with moderate to severe postoperative pain, which may delay mobilization, increase opioid consumption, and impair functional recovery. Ultrasound-guided adductor canal block (ACB) is widely used as part of multimodal analgesia because it provides effective analgesia while preserving quadriceps muscle strength. However, ACB alone may provide insufficient analgesia for the posterior aspect of the knee. The biceps femoris short head (BiFeS) block is a novel ultrasound-guided regional anesthesia technique targeting the posterolateral sensory innervation of the knee and may enhance postoperative analgesia when combined with ACB. However, clinical evidence regarding its analgesic efficacy in patients undergoing total knee arthroplasty remains limited. This prospective, randomized, controlled trial aims to compare postoperative analgesia between ultrasound-guided adductor canal block alone and adductor canal block combined with a biceps femoris short head block in adult patients undergoing primary total knee arthroplasty under spinal anesthesia. Participants will be randomly assigned in a 1:1 ratio to receive either ACB alone or combined ACB plus BiFeS block. The primary outcome is cumulative opioid consumption during the first 48 postoperative hours. Secondary outcomes include postoperative pain intensity, time to first analgesic request, quadriceps muscle strength, functional recovery, postoperative recovery quality, postoperative nausea and vomiting, patient and surgeon satisfaction, length of hospital stay, and block-related complications.
Detailed description
Background Total knee arthroplasty (TKA) is the definitive surgical treatment for end-stage knee osteoarthritis and is one of the most frequently performed orthopedic procedures worldwide. Despite advances in multimodal analgesic strategies, postoperative pain following TKA remains a major clinical challenge. Inadequate pain control may delay early mobilization, impair functional recovery, prolong hospitalization, increase opioid consumption, and reduce patient satisfaction. Therefore, optimization of regional anesthesia techniques continues to be an important component of enhanced recovery protocols after TKA. Ultrasound-guided adductor canal block (ACB) has become a widely accepted motor-sparing regional analgesic technique for TKA because it provides effective analgesia to the anteromedial aspect of the knee while largely preserving quadriceps muscle strength. Nevertheless, the posterior compartment of the knee receives sensory innervation from branches of the sciatic nerve that are not consistently anesthetized by ACB alone. Consequently, residual posterior knee pain remains a common limitation of this technique. The ultrasound-guided biceps femoris short head (BiFeS) block is a recently described regional anesthesia technique that targets the posterolateral sensory innervation of the knee through deposition of local anesthetic within the fascial plane adjacent to the short head of the biceps femoris muscle. Anatomical and preliminary clinical investigations suggest that this technique may provide additional analgesic coverage of the posterior knee while preserving motor function. However, evidence regarding its clinical efficacy as an adjunct to ACB in patients undergoing primary TKA remains limited. Study Objectives The objective of this study is to determine whether the addition of an ultrasound-guided BiFeS block to a standard ultrasound-guided ACB provides superior postoperative analgesia compared with ultrasound-guided ACB alone in patients undergoing primary unilateral TKA under spinal anesthesia. Study Design This is a prospective, single-center, parallel-group, randomized controlled clinical trial. Eligible participants will be randomly assigned in a 1:1 ratio to receive either an ultrasound-guided adductor canal block or an ultrasound-guided adductor canal block combined with a biceps femoris short head block before surgery. All patients underwent total knee arthroplasty under single-shot spinal anesthesia with 15 mg of hyperbaric bupivacaine. No periarticular local infiltration analgesia was performed by the surgical team. Postoperatively, all patients received a standardized multimodal analgesic regimen consisting of intravenous paracetamol (1 g) administered every 8 hours. Rescue analgesia consisted of intravenous tramadol (100 mg), which was administered when the Numeric Rating Scale (NRS) pain score was ≥4. Outcome Assessment The primary endpoint is cumulative intravenous morphine consumption (mg) from arrival in the post-anesthesia care unit until 48 hours after surgery. Secondary endpoints include postoperative pain intensity assessed using the Numeric Rating Scale (NRS), time to first rescue analgesic administration, quadriceps muscle strength, functional recovery assessed by the Timed Up and Go test and knee range of motion, quality of postoperative recovery (QoR-15), postoperative nausea and vomiting, patient and surgeon satisfaction, length of hospital stay, and block-related adverse events. Clinical Significance This study is designed to provide high-quality evidence regarding the potential clinical benefit of incorporating the BiFeS block into contemporary multimodal analgesic protocols for total knee arthroplasty. If the combined regional analgesic approach demonstrates improved postoperative analgesia while preserving motor function, it may represent an effective strategy to facilitate enhanced recovery after surgery and reduce perioperative opioid requirements.
Interventions
An ultrasound-guided adductor canal block will be performed before the induction of spinal anesthesia using a standardized technique. Following ultrasound identification of the adductor canal, 30 mL of 0.25% bupivacaine will be injected into the adductor canal adjacent to the femoral artery to provide perioperative analgesia for primary unilateral total knee arthroplasty.
PROCEDUREUltrasound-Guided Biceps Femoris Short Head Block
An ultrasound-guided biceps femoris short head block will be performed before the induction of spinal anesthesia using a standardized technique. Following ultrasound identification of the fascial plane adjacent to the short head of the biceps femoris muscle, 20 mL of 0.25% bupivacaine will be administered to provide additional posterolateral knee analgesia as an adjunct to the adductor canal block.
Sponsors
Antalya Training and Research Hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Outcomes Assessor)
Intervention model description
Eligible participants will be randomly allocated in a 1:1 ratio to receive either ultrasound-guided adductor canal block alone or ultrasound-guided adductor canal block combined with biceps femoris short head block. Postoperative outcomes will be assessed by an investigator blinded to group allocation.
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* Scheduled for elective primary unilateral total knee arthroplasty under spinal -anesthesia. * American Society of Anesthesiologists (ASA) physical status I-III. * Body mass index (BMI) \<40 kg/m². * Ability to understand the study procedures and provide written informed consent.
Exclusion criteria
* Refusal to participate or inability to provide informed consent. * Body mass index 40 kg/m2 or higher. * ASA physical status IV or V. * Known allergy or hypersensitivity to local anesthetics, opioids, or other study -medications. * Pregnancy or breastfeeding. * Uncontrolled psychiatric disease or severe anxiety interfering with study participation. * Pre-existing neuromuscular disease or peripheral neuropathy involving the operative limb. * Chronic opioid use or opioid dependence. * Chronic pain syndrome requiring regular analgesic therapy. * Severe hepatic or renal insufficiency. * Contraindications to spinal anesthesia or peripheral nerve block, including -coagulopathy, thrombocytopenia, local infection at the injection site, or patient refusal. * Planned bilateral or revision total knee arthroplasty.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Cumulative Opioid Consumption | From arrival in the post-anesthesia care unit until 48 hours after surgery | Cumulative opioid consumption during the first 48 postoperative hours, recorded as intravenous morphine equivalent dose (mg). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Postoperative Pain Intensity | 4, 8, 12, 24, and 48 hours after surgery | Postoperative pain intensity will be assessed using the 11-point Numeric Rating Scale (NRS). Scores range from 0 to 10, where 0 indicates no pain and 10 indicates the worst imaginable pain. Pain will be evaluated both at rest and during knee flexion. Lower scores indicate better postoperative analgesia. |
| Time to First Rescue Analgesic Administration | During the first 48 postoperative hours | Time from completion of surgery to the first administration of rescue analgesic medication, recorded in hours. Longer time intervals indicate prolonged postoperative analgesic effectiveness. |
| Quadriceps Muscle Strength | Preoperatively and at 8, 24, and 48 hours after surgery | Quadriceps muscle strength will be assessed using the Manual Muscle Testing (MMT) Scale, ranging from 0 to 5, where 0 represents no visible muscle contraction and 5 represents normal muscle strength against full resistance. Higher scores indicate greater quadriceps muscle strength. |
| Functional Mobility | 24 and 48 hours after surgery | Functional mobility will be evaluated using the Timed Up and Go (TUG) Test. The total time (seconds) required to stand from a seated position, walk 3 meters, turn, return, and sit down will be recorded. Shorter completion times indicate better functional mobility. Participants who were unable to perform the TUG test independently at 24 hours after surgery were withdrawn from the study according to the study protocol. |
| Knee Range of Motion | Preoperatively and at 12 and 24 hours after surgery | Active knee flexion range of motion will be measured in the supine position using a standard goniometer. The maximum active knee flexion angle will be recorded in degrees. |
| Quality of Recovery at 24 Hours Assessed Using QoR-15 | 24 hours after surgery | Recovery quality will be evaluated using the Quality of Recovery-15 (QoR-15) questionnaire. Total scores range from 0 to 150, with higher scores indicating better postoperative recovery. |
| Postoperative Nausea and Vomiting | Incidence of postopereative nausea and/ or vomiting within 48 hours | The severity of postoperative nausea and vomiting will be assessed using a 4-point ordinal scale (0-3), where 0 = none, 1 = mild, 2 = moderate, and 3 = severe. Lower scores indicate fewer postoperative symptoms. |
| Patient Satisfaction | 48 hours after surgery | Patient satisfaction with postoperative pain management will be assessed using a 5-point Likert scale, ranging from 1 (very dissatisfied) to 5 (very satisfied). Higher scores indicate greater patient satisfaction. |
| Surgeon Satisfaction | At completion of surgery | Surgeon satisfaction with perioperative conditions will be assessed using a 5-point Likert scale, ranging from 1 (very dissatisfied) to 5 (very satisfied). Higher scores indicate greater surgeon satisfaction. |
| Length of Hospital Stay | From end of surgery to hospital discharge, assessed up to 10 days | Length of hospital stay will be defined as the time from completion of surgery until hospital discharge and will be recorded in hours. Shorter hospital stay indicates earlier postoperative recovery. |
| Block-Related Adverse Events | From block placement to hospital discharge, assessed up to 10 days | The incidence of block-related adverse events, including neurological injury, foot drop, local anesthetic systemic toxicity, hematoma, infection, allergic reactions, and myotoxicity, will be recorded. Outcomes will be reported as the number of participants experiencing each event. |
Countries
Turkey (Türkiye)
Contacts
CONTACTNilgun Kavrut Ozturk, MD,Professor
CONTACTSerhat Gulersen, MD,
PRINCIPAL_INVESTIGATORSerhat Gulersen, MD,
University of Health Sciences Türkiye, Antalya Training and Research Hospital
Outcome results
None listed